ISOLATION AND CHARACTERIZATION OF FUNGI ASSOCIATED WITH SPOILED TOMATOES IN MKPAT ENIN L.G.A

CHAPTER ONE

1.0 INTRODUCTION

1.1 BACKGROUND OF THE STUDY

Tomatoes (Solanum lycopersicum) is perishable vegetable widely cultivated and consumed worldwide (Agrios, 2005; Valadez et al., 2012). Originated in West South America (kimura and Sinha, 2008).Tomatoes is an annual plant which belongs to the Solanaceae family. Tomatoes are essential mainly for its dietary needs and can be consumed in diverse ways. It can be cooked as vegetable, as ingredient in many dishes and sauces; in making of stew, fruit and can be eaten raw in salad. It is rich in nutrients, vitamin, dietary fibres and phytochemical (Bradley, 2003; Freeman and Reimers, 2011; Mariga, 2012).They are good source of natural antioxidant which include carotenoids, vitamin phenolic compound Flavonoid which have shown to eliminate free radicals (Sravanthi and Grangadhar, 2005; Pitchaon et al., 2007). Tomatoes has a much lower sugar content than other fruits and is therefore not as sweet and their low pH values make them particularly desirable to fungal decay. Pathogenic fungi, such as Aspergillus, Fusarium, Mucor, Penicillium, Rhizopus, cladosporium species have been implicated in some crop spoilage (Beuchat, 1995). Fungi contamination in many Agricultural Product including tomatoes starts in the fields.

Both biological and physical damage during the harvest and transportation phases, coupled with large amount of water and soft endocarp makes tomatoes more susceptible to spoilage by fungi (Asan and Ekmeiki, 2002). Spoilage of tomatoes are those adverse changes in the quality of tomatoes that are brought about by the action of predominantly biological and physical factors. These may be changes in taste, smell, appearance or texture of the fruit. (Ghosh, 2009) reported that fungi were the source of spoilage of most of the tomatoes sample accessed than bacteria. This fruit are usually displayed on benches and in baskets for prospective customers in the open markets until sold thereby exposing them to further microbial infection beside those associated with these whole fruit surface and those from adjacent infected fruits (Baijewu et al, 2007). Few studies on fungi associated with tomato spoilage are available in Nigeria (Wogu and Ofuase, 2014; Wokoma, 2018; Eni et al., 2010; Bashir et al., 2016). Eating or drinking contaminated foods or drinks can cause food borne disease (Adebajo et al; 2012). Fungal spoilage of tomatoes has been recognized as a source of potential health hazard to humans and animals, they produce mycotoxins which are capable of causing mycotoxicoses in man following ingestion or inhalation (Baker, 2006).The mycotoxins are not limited to their areas of infections. Since tomatoes contain large amount of fluid, these mycotoxins diffuse rapidly throughout them, contaminating all parts and making the fruit unfit for consumption. The importance of tomatoes in the food industry and its nutritional benefits cannot be overemphasized. Routine microbiological examination of tomatoes is very crucial as it contributes to a large extent to economic development.

1.2 JUSTIFICATIONS

Since microorganism have been identified with the major cause of spoilage in fruits and vegetables due to their high water content, proper isolation and characterization of these organism in tomatoes will greatly reduce the spoilage of this perishable fruit and as such producers and consumers will be able to protect their vegetable (tomatoes) and also identify spoiled tomatoes that have been attacked by fungi.

1.3 STATEMENT OF PROBLEMS
One of the risk factors associated with tomatoes is that they contain large amount of water content and soft endocarp which makes them susceptible to spoilage by fungi. The spoiled rotten tomatoes often broken ones are usually preferred by low income earners because of their cheap prices. Spoiled tomatoes can lead to food borne illness and jeopardize the health of the consumers. Proper handling, transportation and thorough washing with clean or chlorinated water will go a long way in reducing the risk of tomato spoilage by fungi. Therefore, there is need to asses those fungi associated with spoiled tomato in order to solve problem of food borne illness which can be pathogenic to human.

1.4 AIM AND OBJECTIVES
This research work will aimed at identifying the various fungi organism associated with the spoilage of fresh tomatoes in Mkpat Enin market.
The Specific objectives of the study include:
To isolate fungi associated with spoiled tomatoes in Mkpat Enin market.
To determine the prevalence of fungal infection on spoiled tomatoes.
To identify and characterize different fungal infection associated with spoiled tomatoes.
To create public health awareness about the excess of fungal in spoiled tomatoes.